The British series, produced by ITV, focuses on a fictional estate in North Yorkshire in the years just before, during and after World War I, including the aristocratic Crawley family that owns it and the servants that keep it running, who range from the upstanding — butler Carson (Jim Carter), valet Mr. Bates (Brendan Coyle) and housemaid Anna (Joanne Froggatt) — to the morally questionable — lady’s maid O’Brien (Siobhan Finneran) and footman Thomas (Rob James-Collier).

As for the family, much of the drama centers on the relationship between Robert Crawley (Hugh Bonneville), the Right Honourable Earl of Grantham, and his wife, American heiress Cora (Elizabeth McGovern), and the romantic complications of their daughters: Lady Mary (Michelle Dockery), Lady Edith (Laura Carmichael) and Lady Sybil (Jessica Brown-Findlay).

Because there is no male Crawley heir, the estate is set to be entailed way to the nearest male relative, the Earl’s third cousin, once removed, Matthew Crawley (Dan Stevens), who has had a torturous, on-again, off-again romance with Lady Mary.

Procter has conceived of a theory regarding Lady Mary’s actual parentage — a theory so far not supported by the narrative of the series — that there may have been a backstairs romance, and that Carson may be Mary’s actual father.

“There’s something unusual between Carson and Mary,” she says. “I think it’s possible. Remember the Crawleys, Cora and Robert, they weren’t entirely in love. she says, ‘It took you two years to love me.’ Carson was an actor, you know. He might have been acting very charming.”

Asked if she could be any character on “Downton Abbey,” which would she pick, Procter says, “O’Brien or Thomas, for sure, because they’re just up to no good. They’re just evil, constantly. Or Mary. Mary’s got a great part. All she does is change her clothes.”

As to which character Procter feels is closest to her own personality, she says, “I think, probably, Sybil, because I was the youngest, and I was the one who was always off volunteering. That would have been me saying, ‘But why not? Why can’t we do that? That isn’t fair.’

“I feel like there’s something about Sybil being the youngest — you’re not sure what she’s doing. She’s just gone for long pieces. I feel like, I’m off doing something.”

Asked which “Downton Abbey” character most resembles Eric, Procter says, “Hmmm, I’m trying to think of who is the most sensitive one. He’s certainly not Mr. Bates. You know, he could be Anna, because you know how Anna is just really solid. But he could be Matthew. He’s certainly the Matthew to Calleigh. Delko is Matthew, and Calleigh is Mary.”

Watching “Downton Abbey” has even helped Procter deal with the seemingly endless delays in moving forward on “CSI: Miami” with the Delko-Duquesne — or “Delquesne” — relationship, which seems to be stuck in perpetual low gear.

“It really bothered me,” she says, “until I saw ‘Downton Abbey,’ and I realized, as a viewer, I loved the carrot on the stick of Mary and Matthew. You’re watching people who are right for each other and have been through enough, that you know are eventually going to get together, with just a little, ‘Eek!’, that they might not.

“With Delko and Calleigh, you know that they still love each other, you know that they’re going to get together. It’s like dessert. You’re looking at it, you know that you’re going to get it later, it’s so good.”